This invention relates to methods for controlling the dosing of detergents in multistage washing machines comprising at least one dispensing compartment and to a control system for carrying out such methods.
Multistage washing machines or those operating on the multibath principle carry out at least two of the following stages: prewash, main wash, final wash, rinsing, softening, acidification, neutralization, disinfection, drying, and so forth. Some of these process stages require detergents or laundry aids whichxe2x80x94in automatic washing machinesxe2x80x94are automatically dispensed into the machine. This generally involves one dispensing compartment per stage, the control system of the washing machine ensuring that the water required to flush the detergent or laundry aid into the machine is delivered to the particular dispensing compartment.
Detergents or laundry aids can be formulated as powders, liquids or pastes. Automatic dosing systems for these products generally receive their control signals from the control system of the washing machine. This applies both to integrated systems and to separate systems whose connection generally entails modification of the washing machine controls. Such systems are complicated andxe2x80x94even if it takes all functions into consideration from the outset on an integrated basisxe2x80x94the hardware is very expensive.
Although the automation of the controls means that user-friendly systems are available at falling prices, the subsequent installation of dosing systems is complicated and expensive because of the necessary modification of the electronic washing machine control system.
The technical problem addressed by the present invention is to develop a dosing control system which works without any need for intervention in the washing machine control system and which enables detergents to be automatically dosed in a simple, uncomplicated manner. According to the invention, the solution to this problem is a method for controlling the dosing to detergents of. The entry of water into a dispensing compartment of the washing machine initiates the introduction of a single predetermined dose of detergent into that dispensing compartment without any need for intervention in the washing machine control system. The introduction of further doses remains blocked pending reactivation. A control system including a master sensor in at least one dispensing compartment of the washing machine without connection to the washing machine controls, is connected by a signal line to a dosing compartment and, whenever water enters such a dispensing compartment equipped with a moisture sensor, a signal is generated and internally processed in the dosing control system, for initiating the introduction of a predetermined dose of detergent into that dispensing compartment.
A dosing control system of this type has the advantage that it can be installed very easily without intervention in the washing machine or the dosing system. A moisture sensor merely has to be provided in those dispensing compartments for whose associated washing stage the automatic dosing of detergents or laundry aids is required. The signal generated by the sensor on the entry of flushing water is relayed to the dosing control system for the particular detergent. In order to ensure that a detergent is only dosed once per washing stage, the signal line is blocked after the first signal contact pending reactivation.
In one particular embodiment of the method according to the invention, which represents an extreme simplification, only the dosing system for the second stage of a two-stage washing process is automated, the dosing system for the first stage being manually initiated with the beginning of the washing process. This manual initiation also reactivates the introduction of a single dose for the second washing stage. In order to be able advantageously to adapt the individual demand situation of the particular washing process in a simple manner, at least a two-stage volume controller is used in another variant of the method according to the invention. A small/large volume can readily be selected for a two-stage process or a small/medium/large volume for a three-stage process, depending on the particular demand of the laundry being washed. In one simple advantageous embodiment, the volume controller is manually adjusted.
The control system according to the invention for the dosing of detergents is so simple and uncomplicated that it can be installed or even subsequently fitted using unskilled labor. The washing machine control systemxe2x80x94unaffected by this installationxe2x80x94ensures that flushing water is introduced into the particular dispensing compartment before the next washing stage. When this flushing water wets the moisture sensor, the start signal is relayed to the dosing system and the particular detergent is introduced into the dispensing compartment with the wetted sensor. In the most simple case, the moisture sensor may consist of a single cable with two exposed terminals which generate a signal on wetting.
There is also no need for intervention in the dosing control system because only the start signal has to be delivered to the dosing system and the dosing control system present in any case then triggers the necessary measures. A preferred embodiment provides a device which ensures that only one dosing operation per washing stage is initiated during a cycle of the washing machine. Otherwise, dosing could be reactivated in a situation where the flushing water is introduced into the dispensing compartment for longer than the time for which detergent has to be dosed. The subject device may advantageously consist of an activator which is designed to be connected to the signal line before the dosing system and which, after the first signal, interrupts the line and can only be reactivated after the start of a new machine cycle.
A volume controller, for example with the settings small/large or small/medium/large, may also be designed as a separate module together with the signal line. This volume controller is connected by the signal line to the dosing control system and can ensure the delivery of a correspondingly predetermined quantity.